Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Middle Irish
airdircus
←
Proto-Celtic
*ɸare-
(derived)
←
Proto-Celtic
*derk-
(mention)
←
Proto-Indo-European
*derḱ-
(root)
←
Proto-Indo-European
*derḱ-
(derived)
←
Middle Irish
airdirc
(affix)
←
Middle Irish
-us
(affix)